Hand-held powered blowers, and especially electric powered blowers, are becoming more and more commonplace in the United States for the cleaning up of lawns and gardens. In lieu of sweeping and raking, these electric blowers facilitate the removal of leaves and grass clippings from turf, and dirt and debris from sidewalks, patios, driveways and other outdoor surfaces.
It is known to modify the electric blowers to provide vacuum ability to the devices, wherein an attachment kit is used to permit a vacuum nozzle to be attached to the impeller inlet of the electric blower, and a collection bag, generally supported by the user's shoulder, is attached to the impeller discharge. To date, however, no gasoline-powered blowers with vacuum capability are on the commercial market in the U.S.
Satoh U.S. Pat. No. 4,451,951 is directed to a vacuum/blower device having a dual opening in an outer surface, with an air switching slide pipe slidable on the surface to selectably determine which opening will be utilized. While no mention of a cooling fan appears in the patent specification, FIG. 2 of the patent drawings appears to disclose the use of coaxial fans (that is, separate cooling fan and impeller).
Damon U.S. Pat. No. 3,417,470 is directed to a hedge trimmer having two handles, each with an associated switch. The front handle is U-shaped, with a switch inside of the handle associated with an actuator which projects through the handle to be easily pulled by an operator as he grips the handle to operate the switch. The switch is a dead-mans switch, as is a similar switch on the second handle, so that if either or both handles are released the switches are opened, automatically stopping the electric hedge trimmer cutting blade.
Knouse U.S. Pat. No. 2,263,136 is directed to a portable saw having a handle with duplex grips thereon. Switch actuating means are associated with each of the grips, and so positioned that upon the user grasping either grip the associated switch may be operated to close the motor circuit and operate the electric saw. Other types of handle/trigger construction are illustrated in U.S. Pat. Nos. 400,890, 1,691,291, 2,159,590 and 2,588,000.
Umbricht U.S. Pat. No. 2,890,660 is directed to a nonclogging centrifical pump designed to specifically reduce the possibility of clogging regardless of the degree of contamination of the liquid being pumped. The impeller blades are tapered to decrease their size from their inner edges to their outer edges to provide relatively high exit velocity and pressure. The bottom edges of the blades, adjacent the liquid inlet, are inclined upwardly and outwardly, and spaced with uniform clearance from the upper inclined surface of the casing ring. The casing ring itself has a slope of 25.degree., which means that the angle of the impeller blade is also 25.degree., extending from the impeller hub to the outer circumference of the impeller in a direction away from the impeller inlet.
Benediker U.S. Pat. No. 3,894,695 is directed to a disintegrator comprising two concentric motor driven rotors rotating in opposite directions, with each rotor carrying at least one circular series of working tools, and at least one of the circular series of working tools being provided with fan blades which extend within the circular series of the working tools, with each fan blade being disposed between two working tools.
Kamelmacher U.S. Pat. No. 3,964,840 is directed to a centrifugal pump impeller blade, wherein the blade includes a pumping surface having concave portions adjacent the blade tip running in to a convex portion adjacent the suction end of the impeller.
Stahle U.S. Pat. No. 4,347,035 is directed to a single-blade impeller centrifical pump useful to transport sewage and the like. The impeller discharge end lies in a radial plane adjacent a housing wall, with a clearance between the housing wall and the discharge end. The blade face is directed to the housing wall to form an acute angle with that wall, with the line between the outer extremity of the blade and the discharge end of the blade forming an acute angle relative to the axial direction of the impeller. The sharpened front edge of the impeller provides a moving shearing edge, and the housing wall provides a stationery shearing edge, so that medium pumped into the impeller can be cut and disintegrated between these edges. The angles defined facilitate drawing long-fibered solids into the area for shearing and disintegration.
Other patents showing the state of the art with respect to impellers and disintegrators include Grothe U.S. Pat. No. 2,126,383, Aurig U.S. Pat. No. 2,338,373 and Pallmann U.S. Pat. No. 3,549,093.